InDesign offers many methods to ensure your photos are placed correctly and without stretching.
Content-Aware Fit is one of the best options and it automatically scales and repositions the image into the frame, based on the context and focal point of the image. Proportions remain intact.
Understanding all your fill options and when to use will help you place images efficiently and correctly.
Fill frame proportionally. This scales horizontally and vertically keeping proportions. It uses the full frame and the image may be larger than the frame/
Fill content proportoinally. This also scales horizontally and vertically keeping proportions constrained, however, the image may not fit frame.
Fit frame to content expands frame to fit content with no regard for overall size. May still need to be scaled to fit on page
Fit content to frame scales content without regard to proportions to fit into the frame. Image may be stretched.